Cloth diapers come in many brands, types, shapes and sizes. Initially, choosing which type of cloth diaper you are going to use can seem overwhelming. The first step to making this choice is to understand what your options are.
An AIO is exactly how it sounds: A diaper with everything you need, all in one fluffy package. No stuffing inserts. No need for a cover. You use the diaper as is. AIOs have a number of absorbent layers on the inside and a waterproof layer on the outside. Everything is sewn together giving you a complete, easy to use diaper.
This is an AIO made by Thirsties that has an absorbent soaker with stay-dry fleece lining and a waterproof exterior.
This is an AIO made by BumGenius that has six layers of absorbent organic cotton sewn into a waterproof cover and snap closures.
An AI2 or hybrid diaper is a two part system that consists of a waterproof cover or shell and inserts that either snap or lay in. The benefit of AI2s is you can change out the inserts and reuse the cover until it becomes soiled.
The Flip System is an AI2 that has a variety of inserts to choose from that lay into the cover making it versatile and user friendly.
GroVia hybrids have a cover with a thin waterproof layer and a variety of soakers to choose from that snap in.
Pocket diapers have a waterproof outer shell and a thin liner that are sewn together. One end is left open, creating a pocket. You then stuff this pocket with an insert or inserts. Pocket diapers give you the option to customize their absorbency to fit your baby's needs.
Stuffing a BumGenius 4.0 pocket diaper is as easy as 1, 2, 3!
Covers are used over a flat, prefold or fitted diaper that is not completely waterproof by itself. Covers are made out of wool, fleece or a laminated cloth fabric called Polyurethane laminate (PUL). Wool covers come in two types - knit and interlock. Both fleece and wool are most commonly made into covers, shorts (shorties) or pants (longies).
This is a Diaper Cover made with PUL
These are Sloomb knit longies and underwoolies.
Interlock and knit wool up close.
Flats & Prefolds
Flats and prefolds are the closest thing to how cloth used to be done back in the day. However, despite how far cloth diapers have evolved, they are still used today as one of the more economical options for cloth diapering. The difference between the two is that flats are one layer of cloth and prefolds have a layered center area for extra absorbency. These pieces of cloth are then folded around the baby and secured with a Snappi, Boingo or pins to keep them intact and finally covered with a diaper cover since they are not waterproof by themselves.
This is a flat folded into quarters - you can see how it is a single layer.
This is an example of a Geffen Baby prefold that has been folded over a baby and secured with a Snappi.
Fitted diapers are very absorbent diapers with soakers that are either sewn in or need to be snapped in. To make these diapers completely waterproof they need a cover. However, many fitteds can go coverless without leaks for up to 4 hours, depending on the diaper.
This organic bamboo fleece fitted (OBF) made by Sustainablebabyish (Sbish/Sloomb) has a snap in soaker that is perfect for daytime use and has an additional lay in soaker that makes this diaper essential for nighttime, especially when covered with Sloomb wool.
Sources: BumGenius/Cottonbabies blog